(a) Field of the Invention
The present invention relates to an eight-speed power train of an automatic transmission.
(b) Description of the Related Art
A typical automatic transmission power train includes several planetary gear sets. The power train receives rotational speed and torque from a torque converter, changes the torque, and transmits the torque to an output shaft.
The larger the number of shift speeds, the better the fuel mileage and performance. A manual transmission that has too many speeds causes inconvenience to a driver. Therefore, power trains with large number of shift-speeds lend themselves best to automatic transmissions.
Durability, efficiency in power transmission, and size of the power train depend a lot on the layout of the planetary gear sets.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.